A VG-TRIO-1 mass spectrometer is requested by a group of six faculty members at Michigan State University, who have ongoing research programs in organic chemistry and biochemistry. The instrument will be installed in the Chemistry department and will be used for the following research: (1) Rapid identification of organic products and organometallic intermediates in a vigorous new effort toward the development of Lewis Acid promoted azaclaisen rearrangements and titanium-mediated carbocyclizations into mild, stereoselective and general synthetic methods (Dr. Stille); (2) Studies in synthesis and functions of novel porphyrins and long-wavelength absorbing photosensitizers for photodynamic therapy (Dr. Chang); (3) Study of novel structures In photochemistry (Dr. Wagner); (4) Design of novel organic structures and new synthetic methods in polycyclic polyarene chemistry (Dr. Hart); (5) Characterization of synthetic intermediates in strained-ring chemistry directed toward the synthesis of natural products (Dr. Reusch); and (6) Determination of products and isotopic label distributions in mechanistic studies of organic reactive intermediate chemistry (Dr. Jackson). The new instrument will replace the currently outdated Finnigan 4000, increasing the resolution, scanning speed, and mass range available on a fast turnaround, routine basis, and improving reliability and student access to the instrumentation. The established durability and ease of maintenance of the TRIO-1 will reduce downtime and decrease the requirement for intervention by technically trained operators-an essential feature as the University's operating costs continue to rise. Drs. Stille, Chang, and Wagner will comprise the major users group, as defined in the application instructions. The instrument will be shared among the major users who have NIH grants but will also be available to other users in the MSU community ontimeavailable basis.